Apparatus for controlling the programming chain of a circular knitting machine

ABSTRACT

Apparatus comprising a first control circuit in which is stored a program for regulating the operation of the normally indexing chain of a circular knitting machine and a second control circuit in series with the first for processing the information received from the first circuit. The second circuit is connected to mechanical elements, actuated by the output of the second circuit, to arrest the normally indexing chain for the period of time necessary to allow operation of the knitting machine to knit a particular section of the knitwork. The control circuits are connected by feedback means from the mechanical elements by which the mutual synchronization of the circuits is affected.

United States Patent 1191 Maler et a1.

1 Sept. 30, 1975 [73] Assignee: Elitex, Zavody textilniho strojirenstvi generalni veditelstvi, Liberec, Czechoslovakia [22] Filed: Mar. 20, 1973 [21] Appl. No.: 342,985

[30] Foreign Application Priority Data Mar. 20, 1972 Czechoslovakia 1844-72 [52] US. Cl. 66/155 [51] Int. Cl. D04B 15/00 [58] Field of Search 66/154 A, 155

[56] References Cited UNITED STATES PATENTS 3.232.079 2/1966 Levine et al. (e/154 A 3.776903 12/1973 Krause 66/154 A FOREIGN PATENTS OR APPLICATIONS 1.583356 9/1969 France 66/l54 A l/1970 Germany 66/154 A 8/1965 United Kingdom....

OTHER PUBLICATIONS The Hosiery Trade Journal, November 1965, pp.

Primary Examiner-Wm. Carter Reynolds [57] ABSTRACT Apparatus comprising a first control circuit in which is stored a program for regulating the operation of the normally indexing chain of a circular knitting machine and a second control circuit in series with the first for processing the information received from the first circuit. The second circuit is connected to mechanical elements, actuated by the output of the second circuit, to arrest the normally indexing chain for the period of time necessary to allow operation of the knitting machine to knit a particular section of the knitwork. The control circuits are connected by feedback means from the mechanical elements by which the mutual synchronization of the circuits is affected.

7 Claims, 6 Drawing Figures 8 5 ,9 11 I 3 15 J I I l 7 l Z s 13 l6 7 IU l2 l4 Sheet 2 of 3 US. Patent Sept. 30,1975

U.S. Patent Sept. 30,1975 Sheet 3 of 3 3,908,406

APPARATUS FOR CONTROLLING THE PROGRAMMING CHAIN OF A CIRCULAR KNITTING MACHINE BACKGROUND OF INVENTION The present invention relates to apparatus for controlling the operation of circular knitting machines and in particular to electronic means for regulating the movement of the normally indexing chain which turns the control drum programing the machine operation.

Knitting machines are well known in which the operation of the needle cylinder and the associated knitting instrumentalities are derived from a control drum which must be turned periodically after the lapse of a pre-determined number of revolutions of the needle cylinder, that is, after the knitting of a certain number of courses. By means of contacts located in predetermined sections of the control drums and levers cooperating therewith, the predefined program located on the face of the control drum is transmitted to the respective instrumentality. On turning the drum a transition from one phrase of the knitting process to another is effected and thereby changes in the knitting can be obtained such as from the formation of the welt to the formation of the leg portion, to the formation of the heel and toe portions in sequence.

The turning of the control drum is generally obtained by means of an indexing or pushing mechanism which is actuated by a mechanical computing device constructed as an endless chain. The chain is composed of a certain number of links and is mounted to move over one or more guide wheels. One of the guide wheels is provided with its own indexing or pushing device in such a manner that the chain is advanced or indexed after a pre-determined number of revolutions of the needle cylinder. Most frequently the chain is advanced by one link after two revolutions of the needle cylinder. Mounted to certain links spaced along the chain are contacts by means of which the indexing device of the control drum is to be actuated. The contacts are spaced in accordance with the number of revolutions the needle cylinder must make for the particular section of the program necessary to knit the knitwork before it is necessary to turn the control drum. The number of revolutions of the needle cylinder between these contacts is determined by the number of links in the chain without contact elements mounted thereon. These intermediate links are smooth and therefore do not make contact with the indexing device for the control drum. Actually, the number of smooth chain links determine the length of the knitwork in each section. As a result in knitting very long knitwork such as pantyhose a very long chain must be provided since a large number of smooth links must be provided corresponding to the length of the leg portion. This advantageously, this results in a large and complex auxiliary mechanism for the normally small knitting machine.

Attempts have been made to shorten the chain by removing the smooth links and employing instead various electromechanical elements, relays, stepping selector switches, and other means which are brought into active position via corresponding switching elements. While these techniques have been successful in shortening the length of the chain they depend for correct and accurate operation upon a continuous supply of electric power. When the power is discontinued for any reason such as an interruption in the power supply, or

the shutdown of the machine in order to repair or replace faulty knitting instruments, the production of bad or faulty knitwork results. Furthermore, these devices have considerable weight and size and a relatively high consumption of power all of which render these devices uneconomical.

It is the object of the present invention to provide means for controlling the operation of the chain in a knitting machine as described which avoids and overcomes the disadvantages of the prior art.

It is a further object ofthe present invention to provide electronic means for regulating the movement of the normally indexing chain which is reliable in its operation, which is economical to fabricate and use and which does not require excess power use.

The foregoing objects, others and numerous advantages of the present invention will be seen from the foregoing disclosure of the present invention.

SUMMARY OF INVENTION Briefly apparatus is provided in accordance with the present invention which comprises a first control circuit in which is stored a program for regulating the operation of the normally indexing chain and a second control circuit in series with the first for processing the information received from the first circuit. The second circuit is connected to mechanical elements, actuated by the output of the second circuit, to arrest the normally indexing chain for the period of time necessary to allow operation of the knitting machine to knit a particular section of the knitwork. The control circuits are connected by feedback means from the mechanical elements by which the mutual synchronization of the circuits is affected.

The present invention is particularly adapted to a circular knitting machine comprising a rotating knitting cylinder having associated knitting instruments which are controlled to produce a sectioned knitwork by a pre-determined program contained on a control drum. The control drum contains a plurality of sections corresponding to the knitwork in which programming means for activating selective knitting instruments and the needle cylinder is provided. The control drum is indexed from section to section by means cooperating with a normally advanceable chain intermittenly moveable in response to a pre-determined number of revolutions of the needle cylinder. According to the present invention mechanical stop means are provided which are engageable with the chain so as to prevent its normal advancement under certain conditions. These conditions are as a result of the integration of a first electronic circuit having a stored program determined with respect to the number of intermittent movements required of the chain to turn the control drum, the number of sections of the knitwork requiring change in selection of the instruments of knitting, and the number of revolutions of the needle cylinder, and a second control circuit for processing said program relative to the actual rotation of the needle cylinder. As a result of the integration of the two circuits the second circuit is caused to produce a signal under selected conditions which actuates the stop means so that the stop means moves into engagement with the chain and prevents its advancement in accordance with the stored program. To complete this system a feedback circuit responsive to the operation of the stop means is provided to control the output of the first circuit so that it operates synchronously with the operation of the second circuit.

Full details of the present invention are given in the following description of the preferred embodiment thereof and are shown by way of example in the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS In the drawings:

FIG. 1 is a schematic diagram showing the connection of the separate members of the control circuits and the mechanical elements connected thereto,

FIG. 2 is a side view, partially fragmented of the mechanical elements for both normally indexing the chain and for selectively preventing such indexing, this figure shows the position of the device wherein the chain may be indexed,

FIG. 3 is a view similar to that of FIG. 2 showing the device in a position wherein the indexing of the chain is prevented,

FIG. 4 is a similar view as FIGS. 2 and 3 showing the retraction of the mechanical stop element and the position of the indexing means preparatory to the further indexing of the chain,

FIG. 5 is an end view of the control drum and the means for indexing it.

FIG. 6 is a circuit diagram illustrating the electronic components found in FIG. 1.

DESCRIPTION OF THE INVENTION Turning first to FIG. 1 the control circuit for processing the information given by the particular program for regulating the control of the chain comprises a scanner 1 or sensing device such as a mechanical follower, by which the number of revolutions of the needle cylinder (not shown) is determined. The scanner 1 is controlled by means (not shown) so that after a predetermined number of revolutions of the cylinder, a pulse is transmitted via line 2 to a pulse generator 3 which produces a driving signal or pulse. This driving signal passes via lines 4 and 5 to a low order counter 6 and via lines 5, 7 through counter 6 and line 8 to a high order counter 9. The output of counter 9 passes through line 10 into an amplifier 11 connected via line 12 to an electromagnet 13 which is in turn connected by means of a mechanical connection 14 to the mechanical stop element 15 by which the advancement of the normally indexing chain may be selectively effected.

The counters 6 and 9 are conventional devices for counting input pulses and to produce an output signal each time a predetermined number has been counted. The counters include memory storage means which may be preset to the predetermined number. Several counters may be cascaded to provide digital read-out if desired in high and low order.

Preceding the above control circuit is a primary control circuit in which a predetermined program for controlling operation of the chain is stored. This circuit consists of a switch 16 having an open contact A and a closed contact B which is directly controlled by the electromagnet 13 with regard to the actual position of the mechanical stop element 15. Thus the control switch 16 is connected via a feedback Z to the position of the mechanical stop element and thus constitutes a mechanism for the mutual synchronization of the operation of the primary control circuit with the circuit for processing the information. The switch 16 is connected via the line 17 to a pulse generator 18 by which a driv' ing pulse is produced and fed over lines 19 to an auxiliary counter 20 which is connected via line 21 to a starting circuit 22.

The auxiliary counter 20 is provided with a plurality of transfluxors or magnetic memory devices, or similar memory members as those in the counters 6 and 9 and its output is connected step-wise via lines 23, 24 and 25 to individual adjustable switch circuits 26, 27 and 28 respectively. Each of the switch circuits 26, 27 and 28 correspond to a position in the control program for the operation of the knitting machine wherein a transition must be made from one section of the control program to a succeeding section of the control program. Accordingly the number of switch circuits may exceed the three shown and in fact will correspond to the number of transitions necessary to affect the total knitwork. The auxiliary counter 20 is also connected via a line 29 to a permanently coded circuit 30 which may be used commonly for those sections of the knitting program which have basically the same interval of operation. Each of the switch circuits 26, 27, 28 and 30 are connected via a connecting line 31 to the low order counter 6 and via a connecting line 32 to the high order counter 9. The switch circuits are conventional devices such as fixed interval switches which are adjustable to provide signal outputs responsive to selected pulse sequences providing a bias to a given memory unit corresponding to a predefined number of pulses on each of the counters 6 and 9.

Since the memory device of the counters 6, 9 and 20 are energized by a pulse in one phase and deenergized by a change in phase each of the counters are arranged accordingly. As seen in FIG. 1, for example, lines 4 and 5 comprise the circuit for one phase while line 8 and lines 4, 7 and 9 comprise the circuit for the other phase. Thus pulses of energizing phase are made to pass sequentially through the low order counter 6 and the high order counter 9, while the deenergizing phase is made to pass through both.

The counters 6 and 9 contain similar memory storage units whereon the driving signals received from the pulse generator 3 are counted in response to a given bias created on the memory storage units by the individual switching circuits 26, 27, 28 and 30. Each counter includes processing circuits, responsive to the counting of a predetermined member, producing a signal over line 10 passing into the amplifier 11. In this manner the number of revolutions actually made by the needle cylinder is sensed by the secondary control circuit (i.e. scanner 1 and counters 6 and 9) and is compared with the number of revolutions recorded in the knitting program, as sensed by the primary control circuit (pulse generator 18, counter 20 and switches 26, 27). The amplifier 11 may be a square wave amplifier producing from a single short pulse a signal sufficiently long and strong enough to operate the electromagnet 13. The switching circuits 26, 27 and 28 are provided with time relays or time delay components whereby the interval of its signal can be adjusted with respect to a pre-determined number of revolutions of the needle cylinder. The auxiliary counter 20 may include a stepping relay which sequentially passes the pulse generated in generator 18 to successive ones of the switching circuits 26, 27, 28 and 39, in accordance with the position of the program of the knitwork.

Turning to FIG. 2, the mechanical construction of the means for indexing and advancing the chain is seen as comprising a pawl 33 which is controlled by an auxiliary mechanism well known and therefore not further described or shown in the present description. Reference may be made to the copending application of the common assignee wherein at least one of the inventors is the same, namely, Ser. No. 342,941, filed on even date herewith, now Pat. No. 3,861,178 issued Jan. 21, 1975, and corresponding to Czechoslovak patent application No. PV 1922-72 dated Mar. 23, 1972. The pawl 33 engages the ratchet teeth 34 35 and the successive teeth of a ratchet wheel 36 which is fixedly attached to a pulley wheel 37 carrying the chain 38. Mounted in spaced intervals along the length of the chain are one or more contact links 39 adapted to engage the means for turning the control drum (not shown). Further details of the control drum and suit able means for its turning can be found in the aforementioned patent. Mounted to swing about a pin 40 is the body of an electromagnet 13 having a pull-in armature 41 at the outer end of which is formed a depending finger 42. Connected to the body of an electromagnet 13 is a frame member 43 which extends below outwardly toward the end of 42 and below the armature 41 is normally extended under bias of a spring 44 and is retracted into the electromagnet 13 only by activation of the electromagnet itself. The frame 43, the pull-in armature 41 and the body of the electromagnet 13 constitute the mechanical elements shown in FIG. 1 and are actuated by operation of the primary and second control circuits shown in the preceding figure.

The drum indexing means is seen in FIG. 5. The lifting link 50 in the chain 38 controls a spring loaded lever 51 which raises a pawl 52 engaging a ratchet wheel 53 of the control drum 54 provided with segments. 55 to control the various operations of the machine. The pawl 52 is controlled via lever 56 from a cam 57, the latter being connected, via a transmission, with the driving mechanism of the needle cylinder.

The lifting (or contact) links 39 and 50 are disposed on the chain in such a way that first the link 50 lifts the lever 51 whereby turning of the control drum 54 is caused, since the pawl 52 engages the ratchet wheel 53. After the chain 38 is next indexed, the lever 51 slips down the lifting link 50 and the finger 42 engages the link 39.

Adjustment of the control circuits shown in FIG. 1 to the specified device to provide selective intervals between two changes in the knitwork program as for example the transition between the welt, the leg or sole portions of a pantyhose is obtained as follows. A selected number of contiguous smooth chain links which are normally found on the chain 38 are removed or taken off from the control chain in those selected sections wherein automatic programming and control operation is desired. The information concerning the number of links which are removed from the chain is inserted in each of the respective adjustable switch circuits 26, 27 and 28 corresponding to that section of the knitwork program. For example the adjustment of the switch circuit 26 may be made to correspond to the number of links removed from the chain for the changes in the welt, the adjustment of the switch circuit 27 can be similarly made for changes in the leg while the adjustment of the switch circuit 28 can be similarly made for that in the sole. The information about the number of movements required to operate the chain for those parts of the knitwork in which the number is either constant or changes only slightly (for example the heel, the toe, or extra courses, etc.,) may be placed into the permanently coded switching circuit 30. Adjustment or change in the information fed to the circuit 30 can be caused by suitably interconnecting the line 29 by standard switch means to any of one lines 23, 24 or 25 for example. As will be seen therefore the chain may be significantly reduced in size by transferring the information contained by the chain in otherwise smooth links into one or more of the switching circuits, of the primary control circuit having regard to the required number of movements otherwise necessary to index the chain in view of the number of sections between transitions in the knitwork program of the machine and the number of revolutions of the needle cylinder itself.

Having thus preprogramed the primary control circuit operation of the device can begin. The knitting machine including the needlecylinder, the knitting instrumentalities, the control drum, etc., all function in the usual and conventional manner and need not be further described herein. The pawl 33 is actuated in response to the pre-determined number-of revolutions of the needle cylinder to engage one'of the teeth 34, 35 of the ratchet wheel 36 so as to periodically turn the chain pulley wheel 37 in the direction of the arrow S. Thus the chain at 38 is itself indexed in intermittent movement in the same direction. At the moment when the contact link 39 indicating a point in the rotation of the needle cylinder wherein a transition must be made in the knitwork program, moves in the direction of the arrow S so that it engages with the depending finger 42 located at the end of the pull-in armature 41, as seen as FIG. 3, the electromagnet 13 is caused to swing about the pivot point 40 clockwise. The electromagnet l3 and its extending armature 41 constitute a two-arm lever which when pivoted closes the switch 16 and places the frame 43 into a position in which the succeeding teeth 35 of the ratchet wheel 36 are covered. On the covering of the ratchet tooth 35 by the frame 43 the normally continuously moving pawl 33 is prevented from engaging the teeth of the ratchet wheel 36 and thus is no longer effective in indexing the ratchet wheel. As a result the mechanical stop means is interposed between the means for indexing the chain and the chain itself and thus constitutes a mechanical stop means for stopping the movement and advancement of the chain 38.

The switch 16 which was simultaneously closed by the movement of the electromagnet 13 causes as is seen in FIG. 1 the production in the auxiliary generator 18 of a driving pulse causing the stepping switch or relay in the auxiliary counter 20 to step to the first switch circuit 26 corresponding to the position of the progress of the knitwork. The pulse generated by the generator 18 is fed by the line 23 into the adjustable switch 26. The output of which is then fed via lines 31 and 32 to the low and high order counters 6 and 9 respectively. Simultaneously the pulse created as a result of the sensing via the scanning I of the actual rotation of the needle cylinder is also passed via the pulse generator 3 as a driving signal via lines 4 and 5 to the low and high order counters 6 and 9 respectively. The signals from the pulse generator are added (or subtracted in the event of a deenergizing pulse) in counters 6 and 9 according to the activation by the switches 26, 27 of the individual memory elements contained therein for a time period determined by the bias of the individual memory storage units made originally on the switching circuit 26. After counting a predetermined number of pulses, relative to the number of rotations of the needle cylinder, that is the interval necessary to produce the number of indexing of the chain 38 under normal conditions, a power pulse appears at the output 10 of the counters 6 and 9 which pass into the amplifier 11 wherein after amplification and shaping in the amplifier a signal is fed to the electromagnet l3 activating the electromagnet itself.

On actuation of the electromagnet 13 the pull-in armature 41 (see FIG. 4) is in fact pulled in against the bias of the spring 44. The finger 42 at the end of the pull-in armature 41 slides over the contact link 39 which as will be recalled had remained in its position under the finger 42 throughout the interval which had been set in the switch circuit 26. On the sliding of the finger 42 from the contact link 39 the electromagnet is swung into its original position because of the weight of the pull-in arm allowing the finger 42 to fall and causing the frame 43 to recede below the level of the teeth 35 of the ratchet wheel 36 uncovering the tooth 35 to engagement by the pawl 33. The pawl 33 thus again causes the indexing of the ratchet wheel 36 and the advancement of the chain at 38 in accordance with its normal behavior.

Simultaneously with the return of the electromagnet 13 to its original position the switch 16 is also caused to be opened thus rendering the primary control circuit open and interrupting power to the electromagnet. Upon the interruption of power of the electromagnet 13 the spring 44 forces the moveable pull-in armature 41 to its original outward position. The reversal of the switch 16 further produces a pulse into the counter 20 which causes its stepping switch or relay to switch sequentially from the switching circuit 26 to that of switching circuit 27 so that the information concerning the operation of the knitting machine in its next section as contained in the switching circuit 27 may be read. The information contained in the switching circuit at 27 is read as soon as the next contact link 39 presents itself beneath the finger 42 and the information from it is passed via lines 31 and 32 into the low and high order counters 6 and 9 respectively as a repetition of the entire cycle stated above occurs.

The number of adjustable switch circuits 26, 27 and 28 and the circuit at 30 having a permanently coded information band is arbitrary and their sequence is given by the interconnection of lines 23, 24, and 29 with those lines 31 and 32. The starting circuit at 22 causes the auxiliary counter 20 to go into operation in its initial position in relation to the advancement of the knitting process itself, that is it initiates the auxiliary counter at the beginning of the knitwork cycle even when not all of the switch circuits 26, 27, 28 are used. Thus the starting circuit 22 returns the stepping switch or other relay mechanism in the auxiliary counter 20 to that corresponding to the switch circuit 26 and corresponding always to the first contact link 39 mounted on the chain 38 in the knitting process.

The operation of the device is further illustrated in FIG. 6 which shows the components used in carrying out the present invention.

The counters 6 and 9 are. as noted earlier, low and high order (decimal/decade) counters having memory storage devices I, ll, lll. X, such as ferrite magnetic elements arranged as phase registers which are excited in one phase and deenergized in the other. The processing circuit of each counter 6 and 9 includes a unidirection thyristor T and capacitor.

The counter 20 is of similar construction to that of counters 6 or 9 but includes a thyristor/capacitor circuit T,, T associated with each of its storage elements (i.e. ferrite cores) so as to limit current flow unidirectional and thus provide a fixed program. Circuits 26 and 27 are adjustable decade/decimal switches transmitting the recorded pulse from lines 23, 24 etc., via their associated diodes into lines 31, 32 and thus to the counter 6 and 9. FIG. 6 shows only one half of each of the circuits 26 and 27 (i.e. that connected to the counter 6) the other half connected to counter 9 is identical. The pulse generators 3 and 18 are conventional. To illustrate the two phase operation the scanner 1 is shown as a switch.

The pulse generator 3 produces a driving pulse on closing of the scanner 1 which passes via line 4 to counter 6 and on opening of the scanner 1 produces a driving pulse passing via line 5 to counter 6. During the interval scanner 1 is closed the generator 3 produces a series of driving pulses via line 4 causing the intelligence stored in core 1, provided this core is provided with a preprogrammed recorded biasing setting imposed on it by its associated half circuit 26, to shift to core ll of the second storage member. On succeeding pulse a further displacement of the intelligence is made until the intelligence from the last core X is displaced, at which time it transfers to core I and simultaneously fires the output thyristor T producing a control pulse passing via line 7 to the counter 9. Since the second phase pulse may also cycle several times, this control pulse generated by pulse generator 3 in response to it also passes through the counter 6 via line 5 and directly into the counter 9 via line 8. Thus the pulse circuit lines for counter 6 comprises lines 4 and 5 while that of counter 9 comprises lines 7 and 8 (line 7 being through counter 6 via line 5).

Thus in this setup a pulse is always generated in line 7, after succeeding multiples of ten cycles in line 4. However, if intelligence is recorded in a memory core other than I of the counter 6, then the first output pulse, in line 7 is produced after as many pulse cycles in line 4 as there are cores after the first core on which intelligence was in fact pre-recorded by the line 31. Thus if for example, intelligence was recorded on the second core from the end (i.e. IX) then an output pulse will be produced in line 7 upon the second closure of switch 1, and during further operation on every twelfth, twenty-second etc. At the production of the output pulse it passes via line 7 to counter 9. The pulse input in counter 9 acts to displace the intelligence imposed on its cores by the pre-recorded program via line 32 in the same manner, until an output pulse is produced in line 10.

There are as many pairs of cores (storage members) in circuit 20 as there are counted sections of the control chain. From each pair of cores, as already described, a line is passed via the associated thyristor T and T ctc., to the appropriate half of circuits 26, 27 etc. The intelligence here is shifted on impulse from the starting circuit 22 from the first storage core to the last,

to pass the pre-programmed recording pulse via lines 23, 24 etc., into the preset switches 26, 27 etc., which indicate the number of links omitted from the counter chain.

The pulse signal output from counter is provided in a similar way, that is by counting the pulse inputs derived from the pulse generator 18. This output is passed via lines 23, 24 etc., to a selected one of the decade/- decimal switches 26, 27 etc., dependent upon the stepping switch located in the counter circuit. Thus the output signal from counter 20 pulses one of the switches 26, 27 etc., which itself may be adjusted to count a series of inputs before providing a signal output. Thus the primary circuit selects the given switch 26, 27 etc., depending on the number of pulses produced by generator 18, while switches 26, 27 et., select the memory storage unit which it is to bias based upon its own preadjustment.

The advantage of the device according to the present invention consists in that a fast readjustment of the individual parts of the knitwork is made possible. The data or information recorded in the counters 6, 9 and 20 are non-destructive and thus even after the knitting machine is shut down in order to remove a possible failure originating as for example by the interruption of the power supply or failure in any one of the instrumentalities of the machine, the advancement of the information as carried out in counters 6 and 9 is continuous and begins in sequence irrespective of the time during which the failure lasted.

It is to be understood that the foregoing disclosure is illustrative of the present invention and that many modifications changes and embodiments are possible for those skilled in the present art. Accordingly, it is intended that the present invention should not be limited by the foregoing disclosure in any way.

What is claimed is:

l. A circular knitting machine comprising a needle cylinder rotating in a plural number of revolutions and associated knitting instruments, a control drum adapted to index about a central axis containing a plural number of sections having programming means for causing operation of said needle cylinder and selective knitting instruments to provide a knitwork having several different sections, a chain, means responsive to a pre-determined number of rotations of said needle cylinder for intermittantly advancing said chain, and means responsive to the advancement of said chain for selectively allowing said control drum to index from section to section in response to a predetermined number of intermittant advancements of said chain, stop means for mechanically preventing normal advancement of said chain, a first control circuit having a stored program determined with respect to the number of intermittent movements of said chain required to index said control drum from section to section, the number of sections of said knitwork requiring change in selection of said instruments and the number of revolutions of said needle cylinder, a second control circuit for processing said program relative to the actual rotation of said needle cylinder, said second circuit producing a signal actuating said stop means to prevent advancement of said chain for an interval in accordance with the stored program, and feedback means responsive to the operation of said stop means for synchronizing the operation of said first and second circuits, said first control circuit comprising a pulse generator producing a driving pulse, a plurality of switch circuits, and a counter having separate memory units each of which are connected to a switch circuit, said switch circuits being collectively connected to the second control circuit, said second control 'circuit comprising a scanner for sensing the number of revolutions of said needle cylinder, a pulse generator, a low order counter and a high order counter, said switch circuits of said first circuit being connected to the low and high order counters respectively, an amplifier connected to the output of said low and high counters the output of which being connected to the means for allowing the control drum to index.

2. The circular knitting machine according to claim 1 wherein at least some of the said switch circuits are adjustable.

3. The circular knitting machine according to claim 1 wherein said chain is mounted on a wheel fixedly arranged with a ratchet wheel, and the means for indexing said chain comprises a moveable pawl engaging the teeth of said ratchet wheel, the stop means for mechanically preventing the advancement of said chain comprising a two armed lever one end of which constitutes an electromagnet, the other end of which constituting an armature therefor, said armature having a finger at the end thereof adapted to engage a contact link on said chain whereby said link may cause said two arm lever to pivot, said stop means further including a frame member extending from the electromagnet beneath the armature adapted to cover the teeth of said ratchet wheel on pivoting of said two armed lever.

4. The circular knitting machine in accordance with claim 3 including spring means for normally biasing said armature outwardly of said electromagnet, said electromagnet being activated to retract said armature in accordance with the pre-determined program thus permitting the two armed lever to return to its original position uncovering the frame member from the teeth of said ratchet.

5. The circular knitting machine according to claim 3 including a switch actuable by pivoting of said electromagnet, said switch being connected to said pulse generator of said first control circuit to thus cause operation of said pulse generator thus constituting a feed back between the first control circuit and the second control circuit via the electromagnet.

6. The circular knitting machine according to claim 4 including a counter, and a starting circuit connected to said counter and said first control circuit for returning the operation of said counter to its initial state.

7. The circular knitting machine according to claim 6 wherein said counters are provided with memory units which are non-destructive.

i l l 

1. A circular knitting machine comprising a needle cylinder rotating in a plural number of revolutions and associated knitting instruments, a control drum adapted to index about a central axis containing a plural number of sections having programming means for causing operation of said needle cylinder and selective knitting instruments to provide a knitwork having several different sections, a chain, means responsive to a predetermined number of rotations of said needle cylinder for intermittantly advancing said chain, and means responsive to the advancement of said chain for selectively allowing said control drum to index from section to section in response to a predetermined number of intermittant advancements of said chain, stop means for mechanically preventing normal advancement of said chain, a first control circuit having a stored program determined with respect to the number of intermittent movements of said chain required to index said control drum from section to section, the number of sections of said knitwork requiring change in selection of said instruments and the number of revolutions of said needle cylinder, a second control circuit for processing said program relative to the actual rotation of Said needle cylinder, said second circuit producing a signal actuating said stop means to prevent advancement of said chain for an interval in accordance with the stored program, and feedback means responsive to the operation of said stop means for synchronizing the operation of said first and second circuits, said first control circuit comprising a pulse generator producing a driving pulse, a plurality of switch circuits, and a counter having separate memory units each of which are connected to a switch circuit, said switch circuits being collectively connected to the second control circuit, said second control circuit comprising a scanner for sensing the number of revolutions of said needle cylinder, a pulse generator, a low order counter and a high order counter, said switch circuits of said first circuit being connected to the low and high order counters respectively, an amplifier connected to the output of said low and high counters the output of which being connected to the means for allowing the control drum to index.
 2. The circular knitting machine according to claim 1 wherein at least some of the said switch circuits are adjustable.
 3. The circular knitting machine according to claim 1 wherein said chain is mounted on a wheel fixedly arranged with a ratchet wheel, and the means for indexing said chain comprises a moveable pawl engaging the teeth of said ratchet wheel, the stop means for mechanically preventing the advancement of said chain comprising a two armed lever one end of which constitutes an electromagnet, the other end of which constituting an armature therefor, said armature having a finger at the end thereof adapted to engage a contact link on said chain whereby said link may cause said two arm lever to pivot, said stop means further including a frame member extending from the electromagnet beneath the armature adapted to cover the teeth of said ratchet wheel on pivoting of said two armed lever.
 4. The circular knitting machine in accordance with claim 3 including spring means for normally biasing said armature outwardly of said electromagnet, said electromagnet being activated to retract said armature in accordance with the pre-determined program thus permitting the two armed lever to return to its original position uncovering the frame member from the teeth of said ratchet.
 5. The circular knitting machine according to claim 3 including a switch actuable by pivoting of said electromagnet, said switch being connected to said pulse generator of said first control circuit to thus cause operation of said pulse generator thus constituting a feed back between the first control circuit and the second control circuit via the electromagnet.
 6. The circular knitting machine according to claim 4 including a counter, and a starting circuit connected to said counter and said first control circuit for returning the operation of said counter to its initial state.
 7. The circular knitting machine according to claim 6 wherein said counters are provided with memory units which are non-destructive. 